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BUG: KASAN: out-of-bounds in unwind_next_frame+0xc4/0xd0 arch/x86/kernel/unwind_frame.c:51
Read of size 8 at addr ffff8801c5727920 by task syz-executor0/13833

CPU: 0 PID: 13833 Comm: syz-executor0 Not tainted 4.9.132+ #51
 ffff8801d0687198 ffffffff81b371b9 ffffea000715c9c0 ffff8801c5727920
 0000000000000000 ffff8801c5727928 1ffff1003a0d0e61 ffff8801d06871d0
 ffffffff81500bad ffff8801c5727920 0000000000000008 0000000000000000
Call Trace:
 [<ffffffff81b371b9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81b371b9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81500bad>] print_address_description+0x6c/0x234 mm/kasan/report.c:256
 [<ffffffff81500fb7>] kasan_report_error mm/kasan/report.c:355 [inline]
 [<ffffffff81500fb7>] kasan_report.cold.6+0x242/0x2fe mm/kasan/report.c:412
 [<ffffffff814f31c4>] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 [<ffffffff810acab4>] unwind_next_frame+0xc4/0xd0 arch/x86/kernel/unwind_frame.c:51
 [<ffffffff81077ccd>] __save_stack_trace+0x7d/0xf0 arch/x86/kernel/stacktrace.c:42
 [<ffffffff81077da8>] save_stack_trace_tsk+0x48/0x70 arch/x86/kernel/stacktrace.c:71
 [<ffffffff816662bf>] proc_pid_stack+0x18f/0x290 fs/proc/base.c:483
 [<ffffffff8165e7fd>] proc_single_show+0xfd/0x170 fs/proc/base.c:785
 [<ffffffff81580d76>] seq_read+0x4b6/0x12d0 fs/seq_file.c:240
 [<ffffffff81509fe5>] do_loop_readv_writev.part.1+0xd5/0x280 fs/read_write.c:718
 [<ffffffff8150b68e>] do_loop_readv_writev fs/read_write.c:707 [inline]
 [<ffffffff8150b68e>] do_readv_writev+0x56e/0x7b0 fs/read_write.c:873
 [<ffffffff8150b954>] vfs_readv+0x84/0xc0 fs/read_write.c:897
 [<ffffffff815ac431>] kernel_readv fs/splice.c:363 [inline]
 [<ffffffff815ac431>] default_file_splice_read+0x451/0x7f0 fs/splice.c:435
 [<ffffffff815ab52c>] do_splice_to+0x10c/0x170 fs/splice.c:899
 [<ffffffff815ab7cf>] splice_direct_to_actor+0x23f/0x7e0 fs/splice.c:971
 [<ffffffff815abf13>] do_splice_direct+0x1a3/0x270 fs/splice.c:1080
 [<ffffffff8150d970>] do_sendfile+0x4f0/0xc30 fs/read_write.c:1393
 [<ffffffff8150f9e1>] SYSC_sendfile64 fs/read_write.c:1448 [inline]
 [<ffffffff8150f9e1>] SyS_sendfile64+0xd1/0x160 fs/read_write.c:1440
 [<ffffffff810056ef>] do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285
 [<ffffffff82803953>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

The buggy address belongs to the page:
page:ffffea000715c9c0 count:0 mapcount:0 mapping:          (null) index:0x0
flags: 0x4000000000000000()
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801c5727800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801c5727880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8801c5727900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                                  ^
 ffff8801c5727980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801c5727a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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